Fellow motorists sprung into action when a driver broke down without a mobile phone on a main road in the US.

The driver had pulled on to the hard shoulder when she ran into trouble but was unable to summon help without her phone.

But she set to work creating a sign which read “Call Police” and other motorists on the L202 in Arizona placed a call on her behalf.

L-202 EB near Williams Fld.: The woman who was driving this maroon car apparently had no cell phone when her car broke down. The resourceful motorist put a sign on her back windshield that said "Call Police." It worked! Within minutes, DPS came to her rescue. #PHXtrafficpic.twitter.com/odHoGnVpqu